tt ? offsetcolor : vec4 (0.0,0.0,0.0,1.0); c2 = ss > thresholdB ? c1 : vec4 (0.0,0.0,0.0,1.0); c2 = tt < thresholdA ? c1 : c2; cBottom = c2; c1 = ss < tt ? offsetcolor : vec4 (0.0,0.0,0.0,1.0); c2 = ss < thresholdA ? c1 : vec4 (0.0,0.0,0.0,1.0); c2 = tt > thresholdB ? c1 : c2; cTop = c2; vec4 newP = vec4 (P0center,P1center,0.0,1.0); vec4 tilecolor = texture2DRect(tex0, vec2(newP)); gl_FragColor = tilecolor + cTop - cBottom; } ]]>